4.4.16 System Failure 19System failure 19 indicates: No Audio Frequency.Cause(s) Action(s)Defective battery Battery is only used for power fail. Try powering up the unit with the batterydisconnected. If the error clears, replace the battery.Defective scale. Disconnect scale connector at probe panel. Power cycle the unit. If the error clears,replace the scale.Defective scaleharness.Disconnect scale harness from J7 on the control board. Power cycle the unit. If theerror clears, replace the scale harness.Defective Servo Oxygenboard.Disconnect the RS485 harness from J8 on the Servo Oxygen board. Power cycle theunit. If the error clears, replace the Servo Oxygen Board.Defective Servo Oxygencable.Disconnect RS485 bus cable from J6 on the control board. Power cycle the unit. Ifthe error clears, replace the RS485 cable going to the Servo Oxygen board.Defective audio circuiton control board.Replace socketed IC U22 on control board. If failure persists, replace the controlboard.Defective control board Replace the control board.4.4.17 System Failure 20System failure 20 indicates: Display WDOG Time Out.Cause(s) Action(s)Display driver board software is not performing correctly. Replace the display driver board.4.4.18 System Failure 22System failure 21 indicates: During operation, the incubator heater will not turn ON.Cause(s) Action(s)Refer to other errors.Power down the unit. During the system tests after power-up the unit should detectsystem failure 15 or bed heater failure. Follow the instructions in this manual forthose failures. Follow the instructions for system failure 15 in section 4.4.13 or for bedheater failure in section 4.3.7.Error readingdistorted line signal.Check the revision of the relay board. The revision code is located in a triangle printedon the component side of the PCB. Refer to relay board Figure 6-34 (revision 10 orhigher) and Figure 6-35 (revision 9 or lower). If the relay board is revision 10 or lower,replace with revision 13 or higher relay board.If you have replaced the relay board with revision 13 or higher and you still have anintermittent problem, follow the instructions for system failure 15 in section 4.4.13.44 6600-0356-000 103 © 2001 by Datex-Ohmeda, Inc.. All rights reserved.Chapter 4: Troubleshooting
